Scammers' phone numbers: how to check an unknown number and why “blacklists” do not help

An unknown number has called, and the first impulse is to type it into a search and see whether it is scammers. “Scammers' phone numbers” is searched for several hundred times a month in Lithuania. Unfortunately, a list of numbers is the weakest protection of all: scammers change numbers faster than anyone can write them down, and some of the numbers on the screen are forged altogether.

This article covers how number spoofing works, what the Communications Regulatory Authority and the operators are already doing about it, what the number on the screen actually tells you and how to behave so that you no longer need to check it.

Why lists of scammers' numbers do not help

• The numbers do not repeat. The Communications Regulatory Authority (RRT) states that random, non-repeating numbers are used for fraudulent calls, so even operators have no way of recognising and blocking them in advance.
• A number can be forged. The caller can set which number you will see on the screen. This is how calls “from the bank” or “from the police” come about.
• The list may contain an innocent person's number. If a real number has been forged, its real owner ends up on the public “blacklist”.
• A clean number does not mean a safe one. The fact that nothing was found online about a number only means that it is new.

That is why there are no specific numbers in this article and there will not be – they would be out of date the same day.

What RRT and the operators are already doing

In Lithuania operators are obliged to apply measures to protect against spoofed calls. Under the procedure set by RRT, the following are blocked or not transmitted:

• calls from abroad that display a Lithuanian fixed-line number;
• calls from numbers for which RRT has not issued authorisations;
• calls coming from abroad with a Lithuanian mobile number when the owner of that number has not gone abroad and is not using roaming.

According to RRT, in the second quarter of 2026 operators blocked 2.78 million calls and 1.22 million fraudulent SMS messages. This is less than in the first quarter, and the authority explains it simply: because of the working filters, it no longer pays for scammers to call with forged Lithuanian numbers.

But the fraud has not disappeared – it has moved:

What the number on the screen tells you

• +370 – a Lithuanian number. This does not mean the call is from Lithuania or that the caller is who they say they are.
• Another code – a call from a foreign number. If you know nobody abroad and are not expecting a call, RRT advises simply not picking up.
• Hidden number – Luminor bank advises caution when no number is visible on the screen or its code is not Lithuanian.
• A call via an app (WhatsApp, Viber) – SEB states that bank employees do not contact customers via messaging apps.
• A short number or a name in the message sender field – this too can be forged, unless the company has protected its name with the operators.

How to check an unknown number

1. Do not call back straight away. A missed call from an unknown foreign number may be bait to call back an expensive number.
2. If an institution introduced itself – find its number yourself: on your bank card, in the contract or on the official website whose address you type in by hand. A genuine employee will not be offended if you call back.
3. If a company introduced itself – check whether that number is listed on its website.
4. An internet search is suitable only as an additional sign. You found complaints – good that you did not believe them. You found nothing – that proves nothing.

What to do once you have answered

SEB states that when calling customers, bank employees never ask you to act quickly, to state an account or card number, online banking, Smart-ID or Mobile-ID codes or to download software.

How to block a number

Blocking protects against the same number, but not against another call tomorrow. For older relatives the most useful thing is to turn on silencing of unknown numbers and to agree: no transfers after a call until it has been talked over.

Where to report

• To your bank – immediately, if you gave details, confirmed a code or transferred money.
• To the police – via epolicija.lt or by calling 112.
• To the National Cyber Security Centre (NKSC) – about a suspicious message or link, by email at cert@nksc.lt.
• To your operator – about a fraudulent call or SMS.
• To the RRT internet hotline svarusinternetas.lt – about other illegal or harmful content online.

Frequently asked questions